The dynamic changes of soil enzyme activity in rhizosphere of two spike-type winter wheat cultivars with different planting densities were studied under field experiments. The results indicated that the activities of protease

catalase and urease of two spike-type winter wheat cultivars presented a single-peaked curve along with growth stage. There appeared the higher values in jointing and heading stage

and the lower values in reviving and anthesis stage. There were different trends of soil enzyme activities in rhizosphere of two spike-type winter wheat cuhivars. To the Yumai 49--198

the activities of protease and urease increased at low planting densities but decreased with the increase in planting density

but change of catalase was not obvious. But to the lankaoaizao 8 all the three soil enzyme activity of decreased at low planting densities but enhanced with the increase in planting density. In addition

the variance analysis showed that the activities of protease and urease reached significant level among different treatments.